Notes on the true History of the Bedouins and Wahabys (Wahabi) sect of Islam by explorer John Lewis Burckhardt.
This is one of the better editions, as it concentrates mostly on History of Islam, even though written by an explorer and traveler of many lands. This is the brand of Islam that is being spread throughout the world these days, so his work is more relevant than might be initially throught. (also details the history of the alliance of the family of Saud and the family of Wahab - Dynastic allegiances DO count under Islam, and very much even to this day, many rulers in Islamic nations today still being actual descendants of the family of Mohammed, such as the Royal family that rules Jordan)
John Lewis Burckhardt was a legend in his day and beyond.